"This is great, come Christmas time I'll get $1,000 bonuses from each of the residents," a former doorman at 740 Park Avenue said.

After all, the building houses more billionaires than any other building in America.

But he thought wrong.

In the new documentary "Park Avenue: Money, Power & the American Dream,” a former doorman of 740 Park Avenue, who wished to remain anonymous, revealed some of the quirks of the building's residents and what it was really like to work there.

"The building is only 31 units, so it's not a lot of residents," the doorman says in the documentary. "But they are high tempered and you need a thick skin to work there. Some are detestable people and they are billionaires."

The doorman revealed:

David Koch was the worst tipper. The doorman would load his two vans every weekend, when Koch was heading to the Hamptons, and he never tipped him.

Some residents would only give a $50 check as a Christmas bonus.

You need to know someone in the business to get a doorman job there.

You had to know which residents liked to open their own door, whose car belonged to whom, which person sat on the passenger side, and who sat in the back seat.

Steve Schwarzman, CEO of the Blackstone Corporation, has 25 Christmas trees delivered to his apartment for his annual Christmas party — one for every room of his home.

The children are all friendly and have special high-fives with the doormen. When they reach about 12 years old, they start ignoring the building's help and start "walking like their fathers." "It's like their parents sat them down and said 'Look this is your life, you are a billionaire. They are not your friends,'" the doorman says.

"One mishap, and you're fired," the doorman says in the film.

740 Park Avenue, on the corner of 71st Street, is currently home to the likes of David Koch, Steve Schwarzman, Ex-Merrill Lynch CEO John Thain, and Vera Wang. The storied building was constructed in 1929 by the grandfather of Jacqueline Kennedy Onassis.